| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for producing a phase shift mask, capable of contributing to fineness and high accuracy of a circuit pattern.SOLUTION: The phase shift mask 20 is obtained by using a phase shift mask blank 10, prepared by forming an ultra-thin film (chromium nitride film) 2 on a quartz substrate 1 for forming a phase shift pattern 1P and further, forming a resist film 3 thereon, as a stock material, and through steps of: forming a resist pattern 3P in the resist film 3; etching the ultra-thin film 2, by using the resist pattern as a mask to form an ultra-thin film pattern 2P; etching the quartz substrate 1 by using the ultra-thin film pattern 2P as a mask to form a phase shift pattern 1P; forming a light-shielding film 4 on the substrate 1, after completing formation of the phase shift pattern 1P and removal of the resist pattern 3 and the ultra-thin film pattern 2P; and selectively etching the light-shielding film 4 by using a resist 5 so as to expose the phase shift pattern 1P, while leaving the light-shielding part 4A at a required portion. The film thickness of the ultra-thin film 2 is set to a minimum thickness necessary to form the phase shift pattern in the quartz substrate 1, by using the ultra-thin film pattern 2P as the mask. |
